Improvement in bit-stocks



`closed to hold the bit therein.

'UNITED SfrA'rns PATENT OFFICE GEORGE W. CHANDLER, OF NEW IPSWIOH, NEW HAMPSHIRE, AND lJOHNG.

FOLSOM, OF WINCHENDON, ASSIGNORS TO JOHN Gr. FOLSOM, OF WINCH-q"1 ENDON, MASSACHUSETTS.

IMPROVEMENT IN BIT-STOCKS.

Specification forming part of Letters Patent No. 146,123, dated January 6, 1874; application filed August 5, 1873. i

State of New Hampshire, and J OHN G. FoL- SOM, of Winchendon, county of Worcester and State of Massachusetts, have invented i certain Improvements in Bit-Stocks, of which the following is a speciiication:

This invention pertains to that class of tools used by workmen for holding bits or drills for boring holes 5 and the invention consists in the peculiar combination of the socket with a pair or more of adjustabletoothed cams, acting as cams and pinions, pivoted in a sliding sleeve within the bindingthimble, which is rotated upon the socket, and in one direction the cams are caused to press against the` staff of the bit or drill, thereby bringing it to the center and forcing it into the socket. A reverse motion will free it from contact therewith, so that it may easily be held and removed at the pleasure of the workman, as will be hereinafter explained.

Figure l is an end view of the socket with the toothed cams shown as open. Fig. 2 is a vertical section of the socket or chuck portion thereof in a plane through the center of the toothed cams, and showing them wide open. Fig. 3 is the same view as Fig. 2, but with the bit inserted, and the toothed cams Figs. 4 and 5 aredetail sections of the parts, as will hereafter appear.

A represents the socket-end of the stock,

the rest being broken away as not necessary to illustrate the invention. B is the binding `thimble or sleeve by which the bits or drills are held or clamped in the chuck. C C are the toothed cams for clamping the staif of i the bit beyond the square, or as shown at Fig. 3, where the bit D is shown inserted in the chuck .of the stock and clamped fast therein. Said toothed cams C C are pivoted in slots or mortises in the outer end lof a sleeve, as at E the inner end of which surrounds the socket A, said sleeve and socket being shown `at Fig. 5, the vertical section being in a plane at a right angle to that of sliding freely at any time, a spiral spring, as

seen at H, surrounds the socket underneath the inner end of the sleeve E to constantly press it outward, and would separate it from v the socket completely were it not prevented by the screw or pin F. On the opposite side of the socket from said screw or pin F a recess and spline may be formed to assist the screw or pin or s tud in holdingu the sleeve in combination with the socket. The pin itself, or a similar one, in addition will, however, answer the purpose, and is a much less expensive device.

As already remarked, the toothed cams C C are pivoted in the outer end of the sleeve E, and, as will be seen in the draw ings, the outer extremities of said cams are provided with teeth that engage with a circular rack on the inner face of the thimble B,

as at K, Figs. 2 and 3, and, consequently, y

when the thimble B is turned to the position shown at Fig. 2 the cams C C will be tilted inwardly, so as to permit the square portion of the bit to be easily inserted, and said cams will remain in said position until the thimble B is turned or screwed down upon the socket, as shown `at, Fig. 3, or where the socket is brought closer to-thelcams, and` where they begin to close and-embrace the staif of the bit below the shoulder of the square, as at L, Fig. 3, and as the thimble B` is forced farther on the screw-thread, as at M, the bit will be forced. firmly between the cams, the parts co-acting like toggle-levers to hold the bit or drill in working position.

This construction of a chuck for bit-stock admirably performs the function of holding the bit or drill firmly endwise in addition to grasping it to hold it in the stock.

We are aware that it is not new to pivot toothed jaws in the head of the chuck, which are operated by a screw-threaded ring or ooil and the socketed stock A, having the serewlar, to throW them in Contact With the bit and thread M, all constructed and arranged to oploek it imposition, and such of itself is not era-te as herein described. claimed by us.

We therefore claim- The sleeve E, having the toothed cams C C Witnesses: pivoted thereto, in combination With the binding-sleeve B, having the rack K at its end, l

GEO. VV. CHANDLER. JOHN G. FOLSOM.

GILES H. WHITNEY, FRANK B. SPATTER. 

